Memory used by caching name server?

[Rob]

Rob wrote:
> 
> Hi,
> 
> This is on FreeBSD 4-Stable.
> 
> I have set up a caching name server. About its cached data base,
> I found out:
> 
>   1) data base is kept in memory
> 
>   2) the maximum memory is adjustable in named.conf, for example:
>         datasize 20M;
> 
> But without specifying the datasize, how much memory is used by
> default. The named.conf man page is rather cryptic:
> 
>    datasize
>        The maximum amount of data memory the server may use.
>        The default value is default.
> 
> 
> Elsewhere, I found that this "default" means a system dependent value.
> 
> In any case, how can I find out what is the memory used by my server
> on my system? Is there a 'ndc <arg>' command for this?
> This is important when I consider to increase the memory limit.

I'm adding additional comments to my own email.

When I do not have the caching name server running, I do this:

   # swapinfo ; ndc start ; swapinfo
   Device          512-blocks     Used    Avail Capacity  Type
   /dev/ad0s1b          99312     3560    95752     4%    Interleaved
   new pid is 1714
   Device          512-blocks     Used    Avail Capacity  Type
   /dev/ad0s1b          99312     3560    95752     4%    Interleaved

No change at all in memory usage. If named keeps its cache in memory,
why do I not see any changes of available swap space when starting named?

Or does named claim memory on the fly, as it is caching?
If so, how can I find out what is the maximum it can claim on my machine?

Thanks,
Rob.